Rotary cutter for excavation, especially for use with raise boring and tunnel boring machines

ABSTRACT

The specification discloses a rotary cutter in which a central support is mounted in a yoke or other supporting structure and which central support rotatably carries a cutting element having a central annular rib in which is mounted hard wear resistant inserts, such as cemented metal carbide inserts.

United States Patent 1191 Goodfellow 1 May 22,1973

54 ROTARY CUTTER FOR EXCAVATION, 3,191,699 6/1965 Robbins et al ..175 374 ESPECIALLY FOR USE WITH RAISE 3,385,385 5/1968 Kucera et a1. ..175/374 BORING AND TUNNELBORING 1,516,340 11/1924 Holdaway et a1. ..175/410 X MACHINES 2,121,202 6/1938 Killgore "175/374 2,223,864 12/1940 Zublin 175/373 [75] Inventor: Robert D. Goodlellow, Bedford, Pa. 2,234,273 3/1941 Pennington ..175/375 3,545,811 12/1970 Montacie 175/375 X [731 Asslgnee: Ken'l'mml Lamb, 3,570,613 3/1971 Coski ..175/374 22 Filed; 2 1971 3,596,724 8/1971 Bechem ..175l410 X [21] Appl' 111,923 Primary ExaminerDavid H. Brown Attorney-Melvin A. Crosby [52] U.S. Cl ..175/374, 175/53 51 Int. Cl. ..E21b 9/22, E21c 13/01 ABSTRACT [58] Field of 23 The specification discloses a rotary cutter in which a I central support is mounted in a yoke or other supporting structure and which central support rotatably carries a cutting element having a central annular rib in [56] References Cited which ismounted hard wear resistant inserts, such as v UNITED STATES PATENTS cemented metal carbide inserts.

3,593,812 7/1971 Peterson ..175/374 x 3 Claims, 1 Drawing Figure PAIENIEB MAY 22 um I U-LLLLLI INVENTOR. ROBERT G-OODFELLO u/ ROTARY CUTTER FOR EXCAVATION, ESPECIALLY FOR USE WITH RAISE BORING AND TUNNEL BORING MACHINES The present invention relates to rotary cutters, especially rotary cutters of the type employed in connection with raise boring and tunnel boring machines.

Cutters of the nature with which the present invention is concerned generally comprise a central supporting structure, such as a shaft, which has its opposite ends supported in a yoke-like arrangement and on which shaft is mounted a rotary cutter member. The particular cutter with which the present invention is concerned has a central annular rib projecting therefrom which is pressed against a formation to be cut while the cutter is moved substantially in the plane of the aforementioned central rib so as to remove material from the formation Cutters of the nature referred to are generally mounted on relatively large supports or heads which are rotated while simultaneously being pressed toward the formation to be cut and in this manner dislodge 'material from the formation. In the main, cutters of the nature referred to are used for cutting, or material removing or excavating operations in connection with rather large holes such as holes for tunnels, or inconnection with enlarging smaller holes, as is done in the mining technique referred to as raise boring wherein a horizontal shaft at one level might be connected with a horizontal shaft at another level.

Cutters of the nature employed in the aforementioned operations are subject to considerable wear and loading and must be capable of withstanding considerable shock and momentary overloads while reducing the formation engaged thereby.

The present invention is concerned with a cutter of the nature referred to so arranged and constructed as to provide for highly efficient reduction of a formation engaged by the cutter. v

The present invention is also concerned with a cutter of the nature referred to which will have relatively long life while remaining in efficient operating condition.

Still further, the present invention is concerned with a cutter of the nature referred to having a steel body formed with a central rib and provided with hard wear resistant inserts, cemented metal carbide, for example, in the rib and so arranged and distributed therein as to provide for efficient reduction of the formation being worked while at the same time protecting the steel of the body of the cutter from being abraded away from the hard inserts which would detract from the support thereof.

The nature of the present invention will become more clearly apparent upon reference to the following detailed specification taken in connection with the accompanying drawing.

BRIEF SUMMARY OF THE INVENTION The cutter of the present invention has a central support shaft on which a pair of antifriction bearings are confined in axial spaced relation between confining end members fixed to the shaft. A steel cutter body is supported on the antifriction bearings and is rotatably confined between the end members and is sealed thereto to maintain lubricant in the space occupied by the bearings while excluding foreign material therefrom.

The rotatable cutter body is formed of steel and has a radially outwardly projecting annular rib, preferably V-shaped in cross section, and having inserted therein hard wear resistant inserts which might, for example, be in the form of a cemented metal carbide such as tungsten carbide.

According to the present invention, the inserts are relatively large in diameter and are staggered along the V-shaped rib of the cutter body so that the sides of the rib are protected while all of the inserts overlap the central plane of the rib and present carbide material to the cutting edge of the rib.

DETAILED DESCRIPTION OF THE INVENTION The drawing shows a stationary support shaft 10 having spaced end members 12 thereon, between which the inner races 14 of a pair of antifriction bearings are confined, and with a spacer member 16 therebetween. The antifriction bearings also comprise rollers 18, cages 20 and outer races 22. Mounted on the outer races 22 is a steel cutter body 24 adapted to be pressed against a formation while the cutters are rolled acrossthe formation so that the cutter will reduce the formation and remove material therefrom.

Body 24 has a central rib 26 which is V-shaped in cross section. The rib 26 is formed with bores 28 and 30 extending substantially parallel to the central plane of rib 26 and radially toward the axis of support member or shaft 10.

The bores 28 are arranged in a plane on one side of the central plane of rib 26 and bores 30 are arranged in a plane on the other side of the central plane of the rib 26 and cylindrical carbide inserts 32 are fixedly mounted in the bores 28 and 30, as by being press fitted into the bores or brazed or cemented therein. Each insert 30 overlaps the central plane of rib 26 and has its outer end formed to a V-shaped configuration so that the outer ends of inserts 32 are substantially flush with the surfaces of rib 26.

The carbide inserts, arranged as shown, present a carbide edge to the formation being cut at the peak and along the sides of the rib and the staggered arrangement of the inserts in the rib reinforces the opposite sides of the rib and prevents rapid wearing away of the steel making up the rotary body 24 so that efficient cutting conditions are maintained while the cutter has long life due to the relatively broad region of the rib which is provided with carbide inserts.

Modifications may be made within the scope of the appended claims.

What is claimed is:

l. A cutter, especially for use in hole forming and enlarging during excavating procedures, and comprising; a support shaft, bearing means on said shaft, end members fixed to said shaft and confining said bearing means therebetween on said shaft, a rotary cutting member formed of steel and surrounding said shaft between said end members and supported on said bearing means, said rotary cutting member having at least one radially outwardly projecting annular rib, said rib being V-shaped in cross section with the peak of the rib outermost, substantially circular radial bores all of the same size formed in said rib and distributed circumferentially about said cutting member, the axes of said bores being in staggered relation relative to the plane of the said peak of said rib and being parallel to the said plane, rod-like inserts circular in cross section formed of hard wear resistant material and having a length greater than the diameter thereof and fixedly mounted in said bores, the diameter of each said bore and of the insert therein being substantially equal to the axial extent of said rib on one side of said peak, each said bore having a minor portion on one side of the plane of said peak of said rib and a major portion on the other side of the said plane whereby said inserts overlap when viewed in the circumferential direction of said cutting member, the outer end of each said insert being wedgeshaped to conform to the shape of said rib and being carbide comprises tungsten carbide. 

1. A cutter, especially for use in hole forming and enlarging during excavating procedures, and comprising; a support shaft, bearing means on said shaft, end members fixed to said shaft and confining said bearing means therebetween on said shaft, a rotary cutting member formed of steel and surrounding said shaft between said end members and supported on said bearing means, said rotary cutting member having at least one radially outwardly projecting annular rib, said rib being V-shaped in cross section with the peak of the rib outermost, substantially circular radial bores all of the same size formed in said rib and distributed circumferentially about said cutting member, the axes of said bores being in staggered relation relative to the plane of the said peak of said rib and being parallel to the said plane, rodlike inserts circular in cross section formed of hard wear resistant material and having a length greater than the diameter thereof and fixedly mounted in said bores, the diameter of each said bore and of the insert therein being substantially equal to the axial extent of said rib on one side of said peak, each said bore having a minor portion on one side of the plane of said peak of said rib and a major portion on the other side of the said plane whereby said inserts overlap When viewed in the circumferential direction of said cutting member, the outer end of each said insert being wedge-shaped to conform to the shape of said rib and being coplanar with the surface of said rib on each side of the said peak of the rib, said bores being so circumferentially spaced that the circumferential distance between the adjacent sides of adjacent ones of said inserts in the plane of said peak is substantially less than the diameter of a said insert.
 2. A cutter according to claim 1 in which said inserts comprise cemented metal carbide.
 3. A cutter according to claim 2 in which said metal carbide comprises tungsten carbide. 